Pitching is a beautiful monster. It's such an elegant art that presents us with a nearly endless stream of data points to pick apart. On the one hand, this gives us a lot to explore and discuss, on the other hand it means there’s plenty of digging to do.

We’re here today to talk about a few more ways to analyze pitchers, with an emphasis on a midseason approach. Preseason analyses can be easier to digest, with huge sample sizes in tow from seasons past. Once the season has started then there’s a whole new batch of curveballs that can be thrown into the equation, from a pitcher’s velocity changing to literally starting to throw a curveball when they hadn’t before.

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Using Pitch Velocity to Analyze Performance

The first component that we’ll look at is velocity, a simple enough measurement to begin with. If a pitcher starts throwing faster, that’s usually a good thing. If a pitcher has lost a few ticks on their pitches, well their effectiveness usually drops and this can actually indicate an underlying injury. Of course pitchers can learn to work with less, but it still presents a hurdle that requires clearing.

Let’s use Felix Hernandez as an example. His average fastball velocity has sat between 93.59 and 92.83 MPH in the past four seasons. Before injuring his calf a few weeks ago, his average fastball velocity has been 90.99 MPH – a notable difference. These are viewable here.

This is not to say that his calf injury was a result of some poor mechanical adjustment that is related to the velocity change, but the dip in velocity does point to some performance woes (that we can see thanks to previous lessons). While Hernandez owners may be pleased with his 2.86 ERA and 1.22 WHIP thus far, his behind the scenes metrics are at career-worst marks. His 4.10 FIP, 4.10 xFIP, 4.29 SIERA, 8.5 percent swinging strike rate and 9.8 percent walk rate are all career-worst marks by far. There is something wrong here, and velocity can certainly be a symptom that helps owners further form an opinion.

Velocity isn’t just the harbinger of doom though! It can bring joy and new pitchers into the spotlight. Just look at Kansas City’s Danny Duffy, who has reemerged as a starter after beginning the season in the bullpen. He averaged roughly 94 MPH on his fastball last season as a starter, and really wasn't that great (before pitching out of the bullpen in the postseason with success - when he could ramp it back up to 97 MPH).

He opened the season in the Royals' bullpen and still had that 97 MPH fastball, but was reinserted into the rotation after others struggles. He's utilized that strong fastball through his first six starts of 2016, keeping his average fastball velocity in the 96 MPH range. Those six starts have yielded a 2.90 ERA with 38 strikeouts and only five walks in 31 innings, in other words he’s doing pretty darn good. Whether he can keep it up or not is another story, and one that his speculators will need to monitor, but this is the springboard into that conversation.

Identifying Recent Trends

We’ve seen that Danny Duffy is doing well, but how can we be sure that we’re looking at relevant information? He’s not going to pitch the same as a starter compared to coming out of the bullpen for just an inning of work. Well, one can go to BrooksBaseball’s Pitchf/x Tool and see the velocity for each appearance he’s made this season.

Ta-da! Also, you can utilize many other variations with the options on the left-hand side of the screen, such as velocity by year, month, game, inning and time through the order.

Thanks to Fangraphs, you can also go to a player’s “Splits” tab and you click “SP/RP” to show their numbers as a starter or as a reliever. These are just a few more tools for the toolbox that are especially helpful for midseason analyses when pitchers can have fluid roles or are experimenting with different approaches.

Differences in Pitch Usage Patterns

There’s much more than just velocity, but in the interest of concision we’re going to just look at one other facet of pitching – the pitches themselves. It’s not enough to say that a guy throws a fastball, changeup, slider and curveball. It’s not enough to say that a pitcher uses his slider a lot. No, we have the actual usage patterns available to us and we’re going to use them!

Take Angels’ pitcher Matt Shoemaker, who has enjoyed recent success after being demoted to the Minor Leagues not long ago due to poor performance. He was brought back up after injuries decimated the Angels rotation with no one expecting anything different, and subsequently gave up seven runs in nine innings across his next two starts. Since then he has given up only eight runs in 38 1/3 innings, striking out 48 while walking only one! What gives?

There are a few factors to consider, but the headliner is that he’s throwing his splitter nearly half of the time compared to roughly 20 percent of the time before this dominant stretch. He’s also totally scrapped his curveball, all of which can be gleaned from that graph. We’ve now got an observable change that coincides with great success, bingo.

The Bottom Line

I realize some of these pages and data groupings can be a lot, but hopefully just focusing on those little pieces within the larger landscapes of information make for a smooth introduction. Focusing on velocity and pitch usage percentages can make for fantastic jumping-off points when conducting investigations.

Changes in performance, for better or worse, can be the result of strange luck fluctuations that can be identified through previously discussed metrics such as BABIP, strand rate, home run rate, walks, hard-hit rate surrendered, and so on. One gains a gigantic advantage when you can identify whether a streak has roots in a legitimate change in approach that warrants re-thinking as opposed to a lucky stretch (the two are not mutually exclusive either).

Being able to differentiate between luck and skill is what allows an owner to make the best pickups, ones that have a much higher chance at sustaining their improved performance and who won’t burn you later. Utilizing these metrics are part of our weekly starting pitcher waiver wire breakdown, and fuels much of our rolling Sleeper & Waiver Wire Pickups List. Bon Appétit!